The Chinese utility model application CN201478933 is known in the prior art, which describes a permanent magnet micromotor, comprising a casing formed by a base and a cover forming a shell internally provided with a Y-shaped stator iron core. The motor comprises a rotor with a permanent magnet, an intermediate shaft parallel to the rotor shaft and an output shaft with an end extending out of the casing. The stator iron core has three teeth with a 60 degrees tooth pitch, with two long teeth surrounded by a coil and a short tooth in the middle.
The European patent application EP1244200 is also known, which describes a stepping motor comprising a rotor having a plurality of magnetic poles along the circumferential direction thereof, a pair of magnetic yokes arranged to face the magnetic poles of the rotor, a pair of field coils for exciting the pair of magnetic yokes, respectively, in response to driving pulses having a phase difference, characterized in that: the stator base is placed close to the rotor, the pair of magnetic yokes are adjusted on the stator base, so that the magnetic paths can be formed respectively, and a pair of pole magnetic stators of the portions formed integrally with the stator base form the magnetic paths as well as the magnetic yokes, respectively.
The Chinese utility model application CN2335297 describes an electric motor which is composed of a driving part, an orientation part and a speed reduction portion. The pole pieces of a stator of the driving part are designed in asymmetrical circular arcs, convex grooves and concave grooves, which can create non-uniform air gaps and can change the magnetic field distribution condition. The orientation part and the speed reduction part have the advantage of a compact and reasonable structure. The utility model can enhance the starting performance and the output torque of miniature motors, can reduce noise and can reduce the additional partial volume.
The document EP0371690 discloses, for example, a transmission mechanism wherein the reduction mechanical assembly is placed at the end of the output axle of the electric motor. Producing mechanical reduction systems with compact gears such as described in the document DE4342185, for instance, is also known. More recently, associating brushless electric motors with such compact reduction systems as described for example in the U.S. Pat. No. 8,403,376 is also known. Associating brushless motors with compact spur-gear reduction systems as described in the patent EP1194999 is also known.
Such devices of the prior art aim at solving the general problem of having a relatively compact mechanical reduction assembly. However, such devices do not make it possible to obtain a very good compactness, or a sufficiently compact motoreducer assembly in specific applications. Particularly for the actuation of a thermal control flap in a motor vehicle, the market demands always more numerous and smaller motoreducer assemblies resulting in a reduced imprint as compared to the current state of the art.
The solutions of the state of the art which use compact reducers having at least two toothed wheel/pinion assemblies per load bearing axle thus do not make it possible to meet the demands imposed in such type of applications, in which a better integration between the motor and the reducer has to be provided, specifically by integrating such elements into a single relatively flat and narrow casing as compared to the existing solutions. The current integrated solutions do not provide for the use of compact enough reduction assemblies.